This study tries to answer some questions in writing fields regarding the most effective ways to give feedback to students’ errors in writing by comparing the effect of three different types of error correction- teacher error-correction, guided error-correction, and self correction- on the improvement of students’ writing ability and to figure out which of these methods help the students improve their future writings. In order to achieve this goal, 90 pre-intermediate English learners were chosen based on an Oxford Placement Test. The learners were studying different fields of medicine at Shahrekord University of Medical Sciences. A pre-test was used to check the initial knowledge of the learners in writing accuracy. In the course of three weeks the participants in all the three groups wrote descriptive paragraphs on different topics and the teacher corrected their writings. In the teacher error correction group, the teacher underlined the errors and wrote the correct form under it. In the guided self error correction group, the teacher underlined the errors and wrote a code under each error and left it to students to correct them, and in the self correction group the teacher just gave a mark to the students’ writing and the students had to work on their mistakes by themselves. After revising the students’ writing on each session and making sure that students had checked their writings and had gone through their errors at home we ask the participants to write on a new topic in the same genre. After three weeks the teacher gave the participants a post test on the same topics to check the learners’ improvement in writing accuracy. In order to analyze the data a t-test was conducted to compare each group performance before and after the treatment and then one way between groups ANOVA was conducted to compare the scores of three groups’ performance in their pretest and post test. The results suggested that guided error-correction led to significant improvement in the learners’ writing performance.
From the above mentioned results it can be assumed that this study can be significant in the sense that errors are a part of learning a new language and teachers should help the students to overcome their mistakes to some extent, not give the students the exact correct answer. Not giving the exact answer will force students to think about their errors, correct them, and better remember the correct forms in their future writing.